Busch, who had dominated the race but lost the lead to Logano on the final restart, was running them down when the collision occurred. Busch squeezed to the outside of Hamlin and shot into the lead while Logano and Hamlin both hit the wall and crashed.

Hamlin’s car spun and slammed nose-first into the inside wall, the impact lifting the front of his car off the ground. Hamlin climbed from his car but sat down on the pavement, where he was attended to by safety workers. He was transported to the infield care center, where he was awake and alert, and was later taken to a local hospital for observation. Hamlin's girlfriend, Jordan Fish, tweeted that Hamlin may have a back injury.

Stewart, meanwhile, was furious with Logano over a late restart. Stewart charged after Logano on pit road and shoved him and took a swing at him before being restrained by the two crews.

"What the hell do you think I'm mad about?" Stewart snapped at a Fox TV reporter. "Some little (expletive) ran us clear down to the infield. He wants to (expletive) about everybody else, but he's the one who drivers like a little (expletive). I'm going to bust his ass."

Logano said he was simply trying to protect his position.

"I had to throw the block; that was the race for the lead," Logano said. "If the 14 (Stewart) got by me, that would have been the end of my opportunity to win the race. I was trying to protect the spot I had."

Busch, meanwhile, rallied to win a race that he had dominated until the wild final restart. The win was his first Cup victory in 31 races, dating back to last April at Richmond. It was his second Cup win at Auto Club Speedway, but the first for Joe Gibbs Racing.

Dale Earnhardt Jr. wound up finishing second in one of the wildest races ever at California. Logano finished third followed by Carl Edwards, Kurt Busch and Greg Biffle.

Hamlin wound up finishing 25th, while Stewart finished 22nd. Points leader Brad Keselowski finished 23rd, allowing Earnhardt to take the points lead after five races.

Busch had come on strong after a slow start to the season, finishing fourth and second in his last two races. He won the Nationwide Series race at California Saturday and then dominated the Cup race on Sunday.

He held the lead on the final restart with 11 laps remaining, but had to deal with a host of hard-charging contenders. Logano held off Stewart on the restart and took off after Busch, taking the lead with seven laps remaining.

Hamlin, who had pitted for four fresh tires during the final caution period, then entered the picture, renewing the rivalry that began last week when he wrecked Logano at Bristol, causing Logano to go after him on pit road after the race.

Logano held the lead on the final lap, but Hamlin caught him and pulled alongside him. As they raced for the lead, Logano drifted up the track, hitting Hamlin in the door as Busch zoomed by on their outside. Busch sped away for the win while Logano and Hamlin both slammed the wall and crashed.

"They forgot about me. I knew they would," he said. "I was hoping I could get by them before they wrecked. When they ran through three and four, I thought, 'This is golden ... I can make this happen.' I put my foot to it and drove by them before they started crashing.

"We weren't going to win it if it hadn't been for their battle there."

Logano had little to say immediately after the race about the collision with Hamlin.

"We were fast and led a lot of laps. There's nothing to hang our heads about," he said.

Logano, who was in a confrontation with another driver for the second straight week, said he would try to smooth things over with Stewart.

"I'll talk to him and we'll see what happens," he said.

Stewart was hearing nothing of it.

"He sent Denny to the hospital and screwed up our day," Stewart said. "He talks the talk but he doesn't walk the walk. He lets his crew guys walk the walk for him. … After he threw a water bottle at my like a little girl, we'll go at it."

Busch dominated the race early, taking the lead from teammate Matt Kenseth and pulling away.

He had to deal with a surprise contender, though, as Joey Logano flashed some speed for the second straight week.

A week after getting wrecked by former teammate Denny Hamlin and confronting him after the race, Logano raced Hamlin hard but clean early in the race at California.

He then took off after Busch, taking the lead from him on Lap 44 and staying with through a round of green-flag pit stops.

Busch regained the lead and dominated the middle portion of the race before Logano swept past him again on a restart on Lap 121.

Several drivers found trouble early.

When Timmy Hill blew an engine on Lap 37, bringing out a caution flag, Clint Bowyer, Brad Keselowski, Kasey Kahne, Jeff Gordon and Kurt Busch all slid in the oil and hit the wall, suffering minor damage to their cars.

Then, during green-flag pit stops, Kevin Harvick and Kurt Busch were both nabbed for speeding. And during another caution period on Lap 91, Keselowski, who had driven into the top 10 after starting at the rear of the field, also was penalized for speeding.

Matt Kenseth also found trouble when he and former Roush teammate Greg Biffle slammed into each other, causing Kenseth to fade with a tire rub. Kenseth had been running in the top five but faded to 26th after pitting under green.

During the next caution period, on Lap 120, Dale Earnhardt Jr. had trouble on his pit stop, spending 20 seconds in his pit stall after a problem on the right rear. Earnhardt dropped from third to 22nd on the ensuing restart.

Logano was leading when another caution flag led to some gambles on pit road. While Busch and Logano took four tires, Tony Stewart, Bowyer, Keselowski and Kenseth all gambled on two, jumbling up the lead pack.

Stewart held the lead on the restart, but Busch needed just 11 laps to charge from 10th to regain the lead.